Additional details of the processes involved in the Choline (Ch+) Ca++ stimulated, model amine secreting system in adrenergic nerve endings were discovered. The establishment of desipramine or cocaine evoked inhibition of Ch+ Ca++ stimulated secretion required Na+ in the external medium, but did not require Na+ to remain in effect. The inhibitors prevented release and stopped on-going release, provided that Na+ was supplied. Potassium prevented the development of inhibition, but did not relieve an established block of Ch+ Ca++ stimulated release. The inhibitors did not block the secretion induced by K+ added to Krebs (KRB) or to the Ch+ Ca++ medium. Thus, the secretions evoked by each of the two stimuli were independent of the other, but involved the same synaptic vesicles. In vivo depolarization would inhibit the Na+ dependent attachment of desipramine to its receptor. Additionally, more recent results on the inhibition of Ch+ Ca++ stimulated secretion by energy conserving nucleotides paralleled the results of published experiment with isolated synaptic vesicles (Euler) more closely than previous experiments. The interaction between ATP and Ca++ was eliminated as a possible mechanism of ATP induced inhibition.